Learn Hardcore Korean: gakkeum gichayeogeseo chingureul mannayo. - I sometimes meet a friend at the train station.

가끔 is an adverb meaning “sometimes” or “occasionally.” It’s used to describe actions that don’t happen all the time but occur from time to time.

What is 기차역?

기차역 is a compound noun made of 기차 (train) + 역 (station). Together, 기차역 means “train station.”

Why is 에서 used with 기차역 instead of 에?

The particle -에서 marks where an action takes place. Since 만나요 (“meet”) is an action, you use 기차역에서 to say “at the train station.”
By contrast, -에 marks a destination or static location and is used with verbs like 있다 (“to be/exist”) or 가다 (“to go”).

Why is 친구 marked with 를 (as 친구를 만나요)?

The particle -를 (or -을 after a consonant) marks the direct object of a verb. Here, 친구 (“friend”) is what you meet, so you attach -를 to show it’s the object of 만나다.

Why is there no subject like 저 or 저는 in this sentence?

Korean often omits the subject when it’s clear from context. If you need to specify, you could say 저는 가끔 기차역에서 친구를 만나요 (“As for me, I sometimes meet my friend at the train station”), but it’s not required.

What is 만나요, and what politeness level is it?

만나요 is the present tense polite form of the verb 만나다 (“to meet”). You take the stem 만나- and add -요 to make it polite informal (often called “반말 vs. 존댓말” middle level).

What is the word order in 가끔 기차역에서 친구를 만나요, and why?

Korean typically follows Time – Place – Object – Verb.

가끔 (Time adverb)
기차역에서 (Place + -에서)
친구를 (Object + -를)
만나요 (Verb)

Can the order of 가끔, 기차역에서, and 친구를 be changed?

Yes. Korean is relatively flexible with adverb and phrase order, so you can say:

기차역에서 가끔 친구를 만나요
친구를 가끔 기차역에서 만나요
The core meaning stays the same, though slight emphasis shifts depending on which element you front.